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| United States Patent |
5,066,713
|
|
Flakus
|
November 19, 1991
|
Process for the preparation of aqueous, radiation-curable
urethaneacrylate dispersions
Abstract
Radiation-curable urethane-acrylate dispersions are obtained by emulsifying
a reaction product of (A) an NCO-containing urethane acrylate prepared by
reacting isophorone diisocyanate with a hydroxylcrylate and (B) a
COOH-containing ester polyol prepared from polyol and an anhydride, such
as trimethyladipic anhydride, maleic anhydride or succinic anhydride.
| Inventors:
|
Flakus; Werner (Recklinghausen, DE)
|
| Assignee:
|
Huels Aktiengesellschaft (Marl, DE)
|
| Appl. No.:
|
502692 |
| Filed:
|
April 2, 1990 |
Foreign Application Priority Data
| Current U.S. Class: |
524/591; 524/539; 528/49; 528/75 |
| Intern'l Class: |
C08G 018/08; C08G 018/67; C09D 175/16 |
| Field of Search: |
528/49,75
524/591,539
|
References Cited
U.S. Patent Documents
| 3929929 | Dec., 1975 | Kuehn | 528/75.
|
| 4094842 | Jun., 1978 | Wenzel et al. | 528/75.
|
| 4123423 | Oct., 1978 | Wenzel et al. | 528/75.
|
| 4131602 | Dec., 1978 | Hodakowski et al. | 528/49.
|
| 4133723 | Jan., 1979 | Howard | 528/49.
|
| 4246391 | Jan., 1981 | Watson, Jr. | 528/49.
|
| 4268426 | May., 1981 | Williams et al. | 528/75.
|
| 4277380 | Jul., 1981 | Williams et al. | 528/75.
|
| 4312798 | Jan., 1982 | Kovacs | 528/75.
|
| 4314922 | Feb., 1982 | Lehner et al. | 528/75.
|
| 4320220 | Mar., 1982 | Pampouchidis | 524/591.
|
| 4339566 | Jul., 1982 | Rosenkranz et al. | 528/75.
|
| 4451636 | May., 1984 | Tsao et al. | 528/75.
|
| 4497932 | Feb., 1985 | Trovati | 524/591.
|
| 4507458 | Mar., 1985 | Shiraki et al. | 528/49.
|
| 4605723 | Aug., 1986 | Flakus | 528/49.
|
| 4608409 | Aug., 1986 | Coady et al. | 528/49.
|
| 4711929 | Dec., 1987 | Stamegna et al. | 524/539.
|
| 4722966 | Feb., 1988 | Flakus | 528/75.
|
| 4730021 | Mar., 1988 | Zom et al. | 524/591.
|
| 4870152 | Sep., 1989 | Meixner et al. | 528/49.
|
| 4874799 | Oct., 1989 | Hung et al. | 528/75.
|
| 4914173 | Apr., 1990 | Ansell | 528/49.
|
| 4920157 | Apr., 1990 | Schulz et al. | 528/75.
|
| 5003026 | Mar., 1991 | Ehrhart et al. | 528/49.
|
Primary Examiner: Kight, III; John
Assistant Examiner: Sergent; Rabon
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt
Claims
What is claimed as new and desired to be secured by Letters Patent of the
United States is:
1. A process for preparing an aqueous, radiation-curable, urethane-acrylate
dispersion, comprising the steps:
(i) reacting isophorone diisocyanate with a hydroxyacrylate at a
temperature of 25.degree. C. to 50.degree. C., in a ratio of equivalents
of NCO to OH of 3:1 to 5:1 to obtain an NCO-containing urethane-acrylate;
(ii) reacting said NCO-containing urethane acrylate with a COOH-containing
ester polyol, prepared from a polyol and a dicarboxylic anhydride, in the
absence of a solvent at a temperature of 50.degree. C. to 100.degree. C.,
to obtain a substantially NCO-free, COOH-containing urethane-acrylate; and
(iii) emulsifying said NCO-free, COOH-containing urethane-acrylate at a
temperature of 85.degree. C. to 95.degree. C. with an aqueous solution of
a base.
2. The process of claim 1, wherein said COOH-containing ester polyol is
prepared from a polyol and an anhydride selected from the group consisting
of trimethyladipic anhydride, maleic anhydride and succinic anhydride.
3. The process of claim 1, wherein the NCO content and the COOH content of
said substantially NCO-free COOH-containing urethane-acrylate are
.ltoreq.0.2% by weight and 1% to 2% by weight, relative to weight of the
solids, respectively.
4. The process of claim 3, wherein the COOH content of said NCO-free,
COOH-containing urethane-acrylate is 1.2% to 1.8% by weight, relative to
the weight of the solids.
5. The process of claim 1, wherein said hydroxyacrylate is hydroxyethyl
acrylate.
6. The process of claim 1, wherein said base is selected from the group
consisting of NaOH, KOH, NH.sub.4 OH, LiOH, and tertiary amines.
7. An aqueous, radiation-curable, urethane-acrylate dispersion, prepared by
a process comprising the steps:
(i) reacting isophorone diisocyanate with a hydroxyacrylate at a
temperature of 25.degree. C. to 50.degree. C., in a ratio of equivalents
of NCO to OH of 3:1 to 5:1 to obtain an NCO-containing urethane-acrylate;
(ii) reacting said NCO-containing urethane acrylate with a COOH-containing
ester polyol, prepared from a polyol and a dicarboxylic anhydride, in the
absence of a solvent at a temperature of 50.degree. C. to 100.degree. C.,
to obtain a substantially NCO-free, COOH-containing urethane-acrylate; and
(iii) emulsifying said NCO-free, COOH-containing urethane-acrylate at a
temperature of 85.degree. C. to 95.degree. C. with an aqueous solution of
a base.
8. The dispersion of claim 7, wherein said COOH-containing ester polyol is
prepared from a polyol and an anhydride selected from the group consisting
of trimethyladipic anhydride, maleic anhydride and succinic anhydride.
9. The dispersion of claim 7, wherein the NCO content and the COOH content
of said substantially NCO-free COOH-containing urethane-acrylate are
.ltoreq.0.2% by weight and 1% to 2% by weight, relative to weight of the
solids, respectively.
10. The dispersion of claim 9, wherein the COOH content of said NCO-free,
COOH-containing urethane-acrylate is 1.2% to 1.8% by weight, relative to
the weight of the solids.
11. The dispersion of claim 7, wherein said hydroxyacrylate is hydroxyethyl
acrylate.
12. The dispersion of claim 7, wherein said base is selected from the group
consisting of NaOH, KOH, NH.sub.4 OH, LiOH, and tertiary amines.
13. A cured film, prepared by curing an aqueous, radiation-curable,
urethane-acrylate dispersion, which is prepared by a process comprising
the steps:
(i) reacting isophorone diisocyanate with a hydroxyacrylate at a
temperature of 25.degree. C. to 50.degree. C., in a ratio of equivalents
of NCO to OH of 3:1 to 5:1 to obtain an NCO-containing urethane-acrylate;
(ii) reacting said NCO-containing urethane acrylate with a COOH-containing
ester polyol, prepared from a polyol and a dicarboxylic anhydride, in the
absence of a solvent at a temperature of 50.degree. C. to 100.degree. C.,
to obtain a substantially NCO-free, COOH-containing urethane-acrylate; and
(iii) emulsifying said NCO-free, COOH-containing urethane-acrylate at a
temperature of 85.degree. C. to 95.degree. C. with an aqueous solution of
a base.
14. The film of claim 13, wherein said COOH-containing ester polyol is
prepared from a polyol and an anhydride selected from the group consisting
of trimethyladipic anhydride, maleic anhydride and succinic anhydride.
15. The film of claim 13, wherein the NCO content and the COOH content of
said substantially NCO-free COOH-containing urethane-acrylate are
.ltoreq.0.2% by weight and 1% to 2% by weight, relative to weight of the
solids, respectively.
16. The film of claim 15, wherein the COOH content of said NCO-free,
COOH-containing urethane-acrylate is 1.2% to 1.8% by weight, relative to
the weight of the solids.
17. The film of claim 13, wherein said hydroxyacrylate is hydroxyethyl
acrylate.
18. The film of claim 13, wherein said base is selected from the group
consisting of NaOH, KOH, NH.sub.4 OH, LiOH, and tertiary amines.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the preparation of aqueous,
radiation-curable urethane-acrylate dispersions, in the absence of
solvents; the dispersions prepared by this process; and cured films of
these dispersions.
2. Discussion of the Background
Radiation-curable dispersions have been developed in recent years. Their
development has resulted from the further development of emulsions
initially cured merely by physical means in the direction of systems which
are thermally or chemically post-cured. Now, films formed, for example,
from unsaturated, aqueous dispersions can be cured and polymerized using
UV, laser or electron beam curing in a few seconds or fractions of a
second.
Radiation-curable, aqueous polyurethane dispersions as described, for
example, in DE-A-3,526,016 have a long shelf life, extending over several
years. The cured films have interesting properties when applied to sheet
steel and are resistant to solvents.
The preparation of emulsions to meet such demanding requirements is very
complex. Initially, saturated and unsaturated polyols are brought into
reaction with for example isophorone diisocyanate in order to form
prepolymers with NCO terminal groups. The system must be diluted with
acetone up to 50% by weight depending on the molecular weight and
viscosity. Then follows the chemical incorporation of surface-active,
ionic reactants, for example, a 30% strength aqueous sodium salt solution
of the appropriate aminocarboxylic acids with the formation of an ionic,
NCO-free prepolymer system which is then emulsifiable in water. Finally,
the auxiliary solvent, for example acetone, is removed by distillation.
Thus, prepolymer formation, dispersion and the removal of acetone by
distillation requires 15 to 25 hours, depending on the structure of the
reactants.
In addition, it is not possible to reuse the acetone distillate directly,
because it contains water.
Against the background of required economy in raw materials and energy, the
process described above for the preparation of such dispersions is
unsatisfactory. Not only the reaction time and the reaction volume, but
also the consumption of solvent and energy are considerable. Moreover, the
urethane-acrylate ionomers which are formed are known to be thermally and
chemically sensitive, i.e., subject to premature polymerization during
prepolymer formation or at least to undergoing gradual changes on
standing.
Any simplification of the process is therefore useless if the shelf life of
the emulsions, which according to DE-A-3,526,016 is required to be some
years, is impaired.
Thus, there remains a need for a process for preparing aqueous,
radiation-curable, urethane-acrylate dispersions which is simple, provides
savings in time and raw materials, and yields dispersion with good
properties and a long shelf life. There is also a need for the dispersions
produced by such a process and cured films of these dispersions.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a simplified
process for preparing aqueous, radiation-curable, urethane-acrylate
dispersions in the absence of solvent, which yields dispersions and cured
films which conform to the highest quality requirements, and the
dispersions and cured films thus-obtained.
It is another object of the present invention to provide a process for
preparing aqueous, radiation-curable, urethane-acrylate dispersions having
a long shelf life.
These and other objects, which will become apparent during the course of
the following detailed description, have been achieved by preparing
dispersions with specific COOH-containing ester polyols. The present
invention therefore relates to a process for the preparation of aqueous,
radiation-curable, urethane-acrylate dispersions, in which isophorone
diisocyanate is initially reacted with a hydroxyacrylate at 25.degree. C.
to 50.degree. C. in a ratio of equivalents of NCO to OH of 3:1 to 5:1 with
the formation of NCO-containing urethane-acrylates, and then the mixture
is further reacted with COOH-containing ester polyols, prepared from
polyols and dicarboxylic anhydrides, in the absence of solvents at
50.degree. C. to 100.degree. C. with the formation of substantially
NCO-free, COOH-containing urethane-acrylates and the mixture is
subsequently emulsified at 85.degree. C. to 95.degree. C. using aqueous
solutions of bases.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Particularly suitable COOH-containing ester polyols are those made from
polyols and trimethyladipic anhydride.
Since the elimination of auxiliary solvents of any kind is an essential
part of the object, all experiments were carried out in the absence of a
solvent.
In the first place it was attempted, when working in accordance with
DE-A-3,526,016, to dispense with the solvent. Doing without, for example,
acetone in the progressive reaction of polyols and isocyanates results in
viscosities of the relevant prepolymers (MW=2,500 to 4,000) which require
working temperatures initially of 60.degree. C. to 80.degree. C., and
finally of 90.degree. C. to 100.degree. C. The viscosity can be controlled
to some extent by using simple mixers, and can be readily controlled using
high speed mixers. Surprisingly, by exercising care, diverse
acryloylurethane systems are obtained in this temperature range. Although
using the acetone method and making rapid additions of aqueous,
surface-active salts of the appropriate amino acids to the prepolymer at
low temperatures results spontaneously in the desired chemical
incorporation of the emulsifier and the formation of the corresponding
ureacarboxylic acids, when solvents are excluded, undesired reactions also
occur.
Thus, at 90.degree. C. to 100.degree. C., not only do the NH.sub.2
equivalents of the surface-active aqueous salt solutions react
selectively, but to a large extent water reacts with the NCO equivalents,
with the elimination of CO.sub.2. This results in the spontaneous and
massive formation of foam in the reactor before any significant amounts of
the surfactant can be introduced. The reactions occurring in a solution of
acetone at low temperatures and without solvent at 90.degree. to
100.degree. C. are contrasted below.
A. The reaction occurring in a solution of acetone at low temperatures:
##STR1##
anionic prepolymer (water-in-oil) system
B. The reaction occurring preferentially at 90.degree. C. to 100.degree. C.
is:
##STR2##
It is clear from this that aqueous surfactant salt solutions at 90.degree.
C. to 100.degree. C. cannot be used. Therefore, diverse surfactant systems
which are either available only as an aqueous solution or as high melting
point salts insoluble in the polymer, are eliminated as possible remedies.
It was also attempted to incorporate the emulsifier with the aid of
dimethylolpropionic acid in the absence of organic solvents.
##STR3##
As is well known, urethane formation is, among other things, considerably
retarded in the presence of acidic groups such as --COOH. Thus, the final
result is a prepolymer low in NCO groups, having an NCO content of about
0.2%. The addition of dilute NaOH, or tertiary amines, and residual
proportions of water initially causes a wetting or organic and aqueous
components, but finally results in a tacky resin which contains water but
is not water-thinnable. Since, in a solution of acetone, DMPA forms
prepolymers with COOH terminal groups, albeit after long reaction times,
which with bases give usable emulsions, it can be inferred that at
relatively high temperatures DMPA enters into side reactions of various
kinds.
The extent of the difficulties encountered--side reactions at many
different levels--is considerable when working in the absence of a solvent
at high temperatures and viscosities, as evidenced by innumerable
unsuccessful experiments. On the other hand, working with a solvent such
as acetone is required to achieve a large measure of reproducible and very
good end products, with conventional dispersions.
In contrast, the process according to the present invention enables
aqueous, radiation-curable, polyurethane emulsions to be expediently and
reproducibly prepared without side reactions or malfunctions at 90.degree.
C. to 100.degree. C. and in the absence of an organic auxiliary solvent.
According to the present invention, isophorone diisocyanate as starting
material is initially reacted with a hydroxyacrylate, such as
2-hydroxyethyl acrylate, i.e., partially acrylated to form component (A).
The formation of (A) is carried out at a temperature of 25.degree. C. to
50.degree. C., preferably 30.degree. C. to 45.degree. C., and the ratio of
the NCO groups of the isophorone diisocyanate to the OH groups of the
hydroxyacrylate is suitably 3:1 to 5:1.
Meanwhile, a polyol, such as trimethylolpropane, butanediol, polyetherdiols
and the like are melted with the addition of a dicarboxylic anhydride,
such as 2,2,4(2,4,4)-trimethyladipic anhydride (TMAA) until the
homogeneous melt has reached about 90.degree. C. to form component (B). At
this temperature, only the formation of acid ester polyols of the
anhydride results, without the elimination of water. Measurement of the
acid number provides a simple method of determining the exact conversion
(conversion 0%=2 COOH equivalents, conversion 100%=1 COOH equivalent).
Further esterification of the acid component is virtually undetectable
below 120.degree. C. Suitably, the anhydride and the polyol are reacted in
relative amounts such that the ratio of OH groups in the polyol and the
anhydride groups is from 7:1 to 11:1, preferably 8:1 to 10:1.
The melt, at a temperature of about 90.degree. C. is advantageously cooled
to about 50.degree. C. and introduced as component (B) into the
preliminary mixture (A) at a rate depending on the heat of reaction, such
that the reaction mixture (A) gradually is heated to a temperature of from
50.degree. C. to 100.degree. C., preferably from 60.degree. C. to
95.degree. C. The viscous prepolymer melt can be stirred in glass vessels
with glass stirrers at 95.degree. C. (high speed mixers are thus not
required).
Component (B) is added to Component (A) in an amount sufficient to obtain a
prepolymer which is substantially free from NCO groups or has a low
content of NCO groups (NCO.ltoreq.0.2% by weight, preferably .ltoreq.0.1%
by weight) but which still has a content of 1 to 2% by weight, preferably
1.2 to 1.8% by weight of COOH relative to the solids. Then, dilute sodium
hydroxide solution is initially introduced and then residual hot water at
85.degree. C. to 95.degree. C., preferably 85.degree. C. to 90.degree. C.,
with stirring. Cooling down leaves a fine-particled, bluish dispersion
with a long shelf life, which after drying by physical means and
radiation-curing gives high gloss films.
The properties of the dispersions prepared according to the present
invention when applied as a film to sheet steel are equivalent to the
systems prepared from a solution in acetone.
The COOH-containing ester polyols may be reaction products of (a) polyol
mixtures of, e.g., trimethylolpropane, aliphatic diols such as ethylene
glycol and homologous such as polyether polyols with (b) dicarboxylic
anhydrides, such as trimethyladipic anhydride (e.g., technical grade
TMAA), maleic anhydride or succinic anhydride, preferably TMAA.
The hydroxyacrylate may be any suitable hydroxy-lower alkyl acrylate.
2-Hydroxyethyl acrylate is a particularly suitable hydroxyacrylate.
Bases used for neutralizing and emulsifying the COO-containing prepolymers
are NaOH, KOH, LiOH, NH.sub.4 OH and/or tertiary amines such as
triethylamine or dimethylaminoethanol, preferably NaOH.
The outstanding thermal and chemical stabilization which acryloylurethanes
acquire from partial esterification with dicarboxylic anhydrides such as
for example TMAA, cannot be conclusively explained, the least so in
comparison with dimethylolpropionic acid.
Trimethyladipic anhydride is a liquid anhydride of low viscosity which is
formed by the thermal elimination of water from trimethyladipic acid with
ring formation. The industrial product contains approximately equal
proportions of the 2,2,4- and 2,4,4-methyl isomers. For convenience, the
acids and corresponding anhydrides are shown below.
##STR4##
After elimination of water:
##STR5##
Other carboxylic anhydrides were tested for suitability in the preparation
of solvent-free, radiation-curable, aqueous emulsions. However, the
results showed that although, related industrially accessible acid
anhydrides can be used in the process, they may give rise to significant
disadvantages. For instance, the use of anhydrides of aromatic character
produces films which yellow during radiation-curing.
Other anhydrides form emulsions having a low solids content and require a
large amount of dilution with water and/or impair the shelf life of the
emulsions.
The advantages of the process according to the invention for the
preparation of aqueous, radiation-curable, urethane-acrylate dispersions
can be stated as follows:
1. The time required for preparing the emulsions is reduced from about 20
hours to 7 hours (see, e.g., Examples 1 and 4);
2. The reaction volume required is reduced by almost 40%;
3. Savings of about 40% by weight (relative to the aqueous emulsion) or
about 100% by weight (relative to the cured coating) of solvent, for
example acetone, and the corresponding distillation costs are obtained;
4. Alkali-resistant coatings are produced from the emulsions prepared
according to the present invention after radiation-curing. The coatings
pass the so-called washing liquor test (exposure to 4% strength NaOH at
80.degree. C. for 3 hours without being affected). Many conventional
anionic dispersions do not meet this standard;
5. The shelf life of the emulsions prepared according to the invention is
excellent and the properties of the emulsions applied to sheet steel are
of a high standard; and
6. The process is very simple to carry out.
Other features of the present invention will become apparent in the course
of the following descriptions of exemplary embodiments which are given for
illustration of the invention and are not intended to be limiting thereof.
EXAMPLES
Comparative Example 1 (Conventional Process: Method of operation employing
a solvent)
Urethane-urea-acrylic dispersions
Basis: Isophorone diisocyanate-polyether/polyols
Surfactant: An aqueous solution of sodium amino-caproate
To a preliminary mixture of 1,110 g of isophorone diisocyanate (IPDI) (5
moles) and 2.8 g of dibutyltin dilaurate (DBTL) are added dropwise with
stirring, initially at 25.degree. C. to 35.degree. C., a mixture of
1,272.7 g of polytetrahydrofuranetherdiol (2 moles), MW about 650,
hydroxyl number 176 mg of KOH/g (TERATHANE.RTM. 650 supplied by DuPont),
235.3 g of 2-hydroxyethyl acrylate (2 moles), hydroxyl number 476 mg of
KOH/g and 134 g of trimethylolpropane (1 mole). The mixture is then heated
to 50.degree. C. to 60.degree. C. until a resin is formed having 1.6% to
1.9% by weight of NCO. After dilution with 2,754.8 g of acetone, 398 g of
the sodium salt of aminocaproic acid in the form of a 30% aqueous solution
are added to the reaction mixture with stirring over a period of 5 minutes
at about 40.degree. C. to 50.degree. C. The reaction mixture is then
dispersed in 3,610 g of water. The acetone-containing, aqueous dispersion
is freed from acetone by distillation. The solids content of the
dispersion is about 42.5% by weight. The preparation time is about 18
hours. The viscosity of the dispersion: DIN cup No. 4:18 sec.
The properties of the films on sheet steel after curing of the dispersion
with the addition of 2.5% by weight of DAROCUR.RTM. 1,116, a commercially
available product supplied by E. Merck, Darmstadt, by exposure to 200
Watt/inch for 5 seconds are given below:
______________________________________
Konig pendulum hardness:
45 sec
(in accordance with DIN 53 157)
Erichsen indentation:
>10.0 mm
(in accordance with DIN 53 156)
Layer thickness: 145 .mu.m
Ultimate tensile strength:
27.2 .+-. 4.5 N/mm.sup.2
(in accordance with DIN 53 455)
Solvent resistance
Abrasion test under 1 kg
load/cm.sup.2
Acetone: no attack after
>100 rubs
Xylene: no attack after
>100 rubs
Washing liquor test:
Result:
Effect of 4% strength NaOH
Film significantly attacked
at 80.degree. C. for 6 .times. 30 min.
after 30 min.
______________________________________
Comparative Example 2 (Acetone-free method according to Example 1)
The ingredients as described in Comparative Example 1 are processed until a
resin is formed having 1.6% to 1.9% by weight of NCO. The reaction mixture
is then heated to 95.degree. C. and 398 g of the sodium salt of
aminocaproic acid are added in the form of a 30% strength aqueous
solution. Pronounced foam formation and gelation of the product is
observed after the addition of only one third of the salt solution.
Comparative Example 3 (Acetone-free method, experiment with
dimethylolpropionic acid)
Basis: Isophorone diisocyanate-polyether/polyols
surfactant: Dimethylolpropionic acid (DMPA)
To an initial mixture of 1,332 g of isophorone diisocyanate (6 moles), 0.17
g of DBTL and 1.6 g of Ionol CP (2,6-di-tert-butyl-4-methylphenol) are
added dropwise with stirring, at 25.degree. C. to 35.degree. C., 358.1 g
of 2-hydroxyethyl acrylate (3 moles) (hydroxyl number: 470 mg of KOH/g)
and stirring is continued until a resin is formed having 22.4% to 23.4% by
weight of NCO. Then, 1,260.7 g of polytetrahydrofuranetherdiol (2 moles)
MW abut 650, hydroxyl number 178 mg of KOH/g (TERATHANE.RTM. 650 supplied
by DuPont), 134 g of dimethylolpropionic acid (1 mole), 134 g of
trimethylolpropane (1 mole), 3.2 g of dibutyltin dilaurate are added and
the reaction temperature is increased from 35.degree.-45.degree. C. to
90.degree. C., until a NCO content of 0.2% to 0.3% by weight has been
reached. Then 400 g of 10% strength sodium hydroxide solution (40 g of
NaOH+360 g of H.sub.2 O) (1 mole) are introduced, and the reaction mixture
is homogenized and diluted with 4,467 g of hot water. A rubber-like solid
forms, and phase separation occurs after a few hours.
Example 4 (According to the Present Invention)
Basis: Isophorone diisocyanate/polyether-polyols
2,2,4-(2,4,4)-trimethyladipic anhydride
A) To a preliminary mixture of 1,110 g of IPDI (5 moles) and 0.13 g of
dibutyltin dilaurate (DBTL) and 1.5 g of Ionol CP
(2,6-tert-butyl-4-methylphenol) are added dropwise with stirring, at
25.degree. C. to 35.degree. C., 238.7 g of 2-hydroxyethyl acrylate (2
moles) (hydroxyl number 470 mg of KOH/g) until a resin has been formed
with a NCO content of 24.9% to 25.9% by weight (A). Then, 1,657.7 g of
reaction product (B) described below are introduced into the preliminary
mixture (A), and the reaction temperature is brought to 90.degree. C. to
100.degree. C. in accordance with the viscosity and heat of reaction.
Reaction Product (B)
______________________________________
1,260.7 g of
polytetrahydrofuranetherdiol (2 moles)
MW about 650, hydroxyl number 178 mg of
KOH/g, (TERATHANE .RTM. 650 supplied by
DuPont);
90 g of 1,4-butanediol (1 mole);
134 g of of trimethylolpropane (1 mole); and
170 g of of trimethyladipic anhydride (1 mole)
______________________________________
are heated to 90.degree. C., and formation of the semi-ester occurs which
is characterized by an acid number of 34 mg of KOH/g. After cooling the
mixture to 50.degree. C., 3 g of dibutyltin dilaurate ar introduced.
Into the prepolymer (prepared from (A) and (B)) having a NCO content of
about 0.2% by weight, are introduced 400 g of 10% strength NaOH (40 g of
NaOH+360 g of H.sub.2 O) (1 mole of NaOH), and the mixture is homogenized
at 85.degree. C. to 90.degree. C. Addition of 4,145.1 g of H.sub.2 O leads
indirectly to a fine-particled bluish emulsion of about 40% strength. The
preparation time is about 6 hours.
Viscosity of the dispersion: Ford cup No. 4 (16 sec).
The properties of the films on sheet steel after curing of the dispersion
to which 2.0% by weight of DATOCUR.RTM. 1,173 have been added, by exposure
to 200 Watt/inch for 5 seconds are given below:
______________________________________
Konig pendulum hardness:
42 sec
(in accordance with DIN 53 157)
Erichsen indentation:
>10.0 mm
(in accordance with DIN 53 156)
Layer thickness: 130 .mu.m
Ultimate tensile strength:
32.5 .+-. 3.1 N/mm.sup.2
(in accodance with DIN 53 455)
Elongation at break: 141 .+-. 14%
Solvent resistance
Abrasion test under 1 kg
load/cm.sup.2
Acetone: no attack after
>100 rubs
Xylene no attack after
>100 rubs
Washing liquor test: Result:
Effect of 4% strength NaOH
No attack after
at 80.degree. C. for 6 .times. 30 min.
6 .times. 30 min.
______________________________________
Example 5 (According to the present invention)
Basis: Isophorone diisocyanate/polyether-polyolsmaleic anhydride
The preliminary mixture of ingredients as described in Example 4 is
processed until a resin is formed having a NCO content of 24.9% to 25.9%
by weight (A). Then 1,585.6 g of reaction product (B) described below is
introduced into the preliminary mixture (A) and the reaction temperature
is brought to 90.degree. C. to 100.degree. C. in accordance with the
viscosity and heat of reaction.
Reaction Product (B)
______________________________________
1,260.7 g of
polytetrahydrofuranetherdiol (2 moles)
MW about 650, hydroxyl number 178 mg of
KOH/g, (TERATHANE .RTM. 650 supplied by
DuPont);
90 g of 1,4-butanediol (1 mole);
134 g of of trimethylolpropane (1 mole); and
98 g of of maleic anhydride (1 mole)
______________________________________
are heated to 90.degree. C., and a semi-ester is formed, characterized by
an acid number of 35.5 mg of KOH/g. After cooling the mixture to
50.degree. C., 2.9 g of dibutyltin dilaurate are introduced.
Into the prepolymer (prepared from (A) and (B)) having a NCO content of
about 0.2% by weight, are introduced 400 g of 10% strength NaOH (40 g of
NaOH+360 g of H.sub.2 O) (1 mole of NaOH), and the mixture is homogenized.
5,084 g of H.sub.2 O are added to obtain indirectly a fine-particled
bluish emulsion of about 35% strength. The preparation time is about 6
hours.
Viscosity of the dispersion: Ford cup No. 4 (25 sec).
The properties of the films on sheet steel after curing of the dispersion
to which 2.0% by weight of DAROCUR.RTM. 1,173 (relative to the resin) have
been added by exposure to 200 Watt/inch for seconds are given below:
______________________________________
Konig pendulum hardness:
80 sec
(in accordance with DIN 53 157)
Erichsen indentation:
>10.0 mm
(in accordance with DIN 53 156)
Layer thickness: 101 .mu.m
Ultimate tensile strength:
30.8 .+-. 2.9 N/mm.sup.2
(in accordance with DIN 53 455)
Elongation at break: 70 .+-. 11%
Solvent resistance
Abrasion test under 1 kg
load/cm.sup.2
Acetone no attack after >100
rubs
Xylene no attack after >100
rubs
Washing liquor test: Result:
Effect of 4% strength NaOH
No attack after
at 80.degree. C. for 6 .times. 30 min.
6 .times. 30 min.
______________________________________
Example 6 (According to the present invention)
Basis: Isophorone diisocyanate/polyether-polyols-succinic anhydride
The preliminary mixture of ingredients as described in Example 4 are
processed until a resin is formed having a NCO content of 24.9% to 25.9%
by weight (A). Then 1,587.6 g of reaction product (B) described below are
introduced into the preliminary mixture (A) and the reaction temperature
is brought to 90.degree. C. to 100.degree. C. in accordance with the
viscosity and heat of reaction.
Reaction Product (B)
______________________________________
1,260.7 g of
polytetrahydrofuranetherdiol (2 moles)
MW about 650, hydroxyl number 178 mg of
KOH/g, (TERATHANE .RTM. 650 supplied by
DuPont);
90 g of 1,4-butanediol;
134 g of of trimethylolpropane; and
100 g of of succinic anhydride
______________________________________
are heated to 90.degree. C., and a semi-ester is formed, characterized by
an acid number of 35.4 mg of KOH/g. After cooling the mixture to
50.degree. C., 2.9 g of dibutyltin dilaurate are introduced.
Into the prepolymer (prepared from (A) and (B)) having a NCO content of
about 0.2% by weight, are introduced 400 g of 10% strength NaOH (40 g of
NaOH+360 g of H.sub.2 O) (1 mole of NaOH) and the mixture is homogenized.
The addition of 4,854 g of H.sub.2 O produces indirectly a fine-particled
bluish emulsion of about 36% strength. The preparation time is about 6
hours.
Viscosity of the dispersion: Ford cup No. 4 (26 sec).
The properties of the films on sheet steel after curing of the dispersion
to which 2.0% by weight of DAROCUR.RTM. 1,173 (relative to the resin) have
been added, by exposure to 200 Watt/inch for seconds are given below:
______________________________________
Konig pendulum hardness:
65 sec
(in accordance with DIN 53 157)
Erichsen indentation:
>10.0 mm
(in accordance with DIN 53 156)
Layer thickness: 99 .mu.m
Ultimate tensile strength:
31.0 .+-. 3.7 N/mm.sup.2
(in accordance with DIN 53 455)
Elongation at break: 119 .+-. 16%
Solvent resistance
Abrasion test under 1 kg
load/cm.sup.2
Acetone: no attack after
>100 rubs
Xylene: no attack after
>100 rubs
Washing liquor test: Result:
Effect of 4% strength NaOH
No attack after
at 80.degree. C. for 6 .times. 30 min.
6 .times. 30 min.
______________________________________
Obviously, numerous modifications and variations of the present invention
are possible in light of the above teachings. It is therefore to be
understood that, within the scope of the appended claims, the invention
may be practiced otherwise than as specifically described herein.
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